Other Examples

Some rather strange one-off examples of alkaloids have been found. The water skater Stenus comma produces stenusin, or 3-(2/-methylbutyl)piperidine (Figure 9.13) in its pygidial gland, probably as an antibiotic substance. A phasmid insect (Oreophoetes peruana) stores quinoline, as the single component in its thoracic glands. It is probably made from anthranilic acid. The compound is repellent and topically irritant to ants, spiders and cockroaches. The pale-brown chafer beetle Phyllopertha diversa uses an alkaloid as its female sex pheromone. The l,3-dimethyl-2,4-quinazolinedione (Figure 9.13) evidently comes from anthranilic acid. Equally curious is the discovery that only the males of this species possess a cytochrome P450 specifically for breaking down this compound (by demethylation of N-l and hydroxylation of the aromatic ring). The sex pheromone of the longhorn beetle Migdolus fryans, which